1. Field of the Invention
This invention relates to a process and an apparatus, particularly to an apparatus of the rotor and barrel type for the factory processing of thermoplastic and rubber like or polymeric materials up to the quality obtained by the small laboratory equipment.
2. Description of the Prior Art
The normal two roll factory size two roll mill produces a bank of material between the two rolls into which arriving process material must push its way into the bank. This action wastes the work that was used to extrude the material. Massed material in the bank is sheared by the action of the two rolls, an action referred to as turbulent flow and considered excellent. However, the imposed shear is directed to the path of least resistance, the already worked material and increases the non-uniformity of the processing. Additional working tends to hide the unequal processing, but can never equal the quality of uniformity processed material. Mills following a #27 internal mixer varies from two to seven mills, which complete the processing. Also, even if one mill was used, a mill man had to be in attendance to start and stop the feed strips as required.
This was the start of the art at the time of change over to radial ply tires. A massive millroom study was made in which all compounds were measured at each step of the mixing process. After hundreds of complete tests it became evident that a certain minimum of power, regardless of the equipment used, was required to obtain designed quality. Additional mixing with added power input was shown not to be cost effective. Thus the millroom state of the art made it cost effective to change over to radial ply tires.
Now, some forty years later, it is time to modernize the mixing process.